a) Field of the Invention
The present invention relates to a method of producing a prism for use in an optical path synthesizing element or optical path separation element and the like. It also relates to an optical head apparatus that is equipped with a prism.
b) Description of the Related Art
Generally, the optical head apparatus used for recording and reproducing data on an optical data storage medium such as a CD or DVD comprises a laser emitting element, a prism that is entered by a laser beam emitted from a laser emitting element, a collimating lens for collimating the laser beam emitted from a laser emitting element that passes through a prism, and an objective lens for condensing the parallel beams emitted from the collimating lens to an optical data storage medium wherein these components are arranged along the optical path in the order given.
In an optical head apparatus of this type, a prism is used as an optical path synthesizing element or optical path separation element. For example, in the optical system as illustrated in FIG. 1, a prism is used as an optical path separation element: Prism 4 comprises first prism component 41 and second prism component 42 joined together along partial reflection plane 43, which is inclined with respect to the optical axis L of the laser beam emitted from laser emitting element 2. Partial reflection plane 43 transmits the laser beam emitted from laser emitting element 2 to collimating lens 5 while it reflects the light returned by optical data storage medium 20 to light receiving element 9.